Reciprocating ram pump



y 1952 J. M. TOWLER ET AL 5 RECIPROCAT-ING RAM PUMP F iled Jan. 12, 1946 Patented July 29, 1952 l I 2,604,855 g RECIPROCATING RAM PUMP g E f .lol m Maurice ,Towler, H a"F ;a Hathorn ,Towler, Otley, England, assigno-rs Electraulic Presses Limited, Rodley, England, v a corporation of England 1 l Application January'l2, 1946, Serial as v In Great Britain February 5,1945

- {3 cla ms. (01. 103-453) Thisi'nventionrelates to reciprocating ram pumps which can be used for supplying liquid at pressures up to 5000 lbs. per square inch and over, such as the pumpaccording to U. S. Patent No. 2,168,850, which has aseating at the inner end of eachpump borejtoreceive a mushroom type inlet valve whichiop'ensflin an inward direction and the face of which is opposed endface of, thepump ram.

At the very highflpressures referred to above the question of str'fesslbec'omes of vital importance and the presence o'f'a stress concentrationinthe pump body may lead to its fracture. Such a stress concentrationfwill be caused by a change in section in the wall of thepump bore on the pressure side of the ram. Such a change in. section is produced in pumps'as now constructed by the constriction inthe diameterof the pump bore to formrthe inlet valve seating, A further 'disadvantage of 'such'constriction is that it is almost impossible, by known machining methods to ob'-: tain the desired degree of parallelism throughout the eiiective length of the pump bore;

The object of'the present invention is to provide a construction of pump which will both eliminate the above change in section and facilitate the machining of the pump-bores.

In a pump according to the present invention each pumpbore' consists of a parallel hole extending right through the block of metal constituting the pump body and the seating for the inlet valve forms part of a separate member or bushing which fits into one end of the pump bore.

In order that the invention may be clearly understood and carried into efiect we will now describe, by way of example, an embodiment consisting of a reciprocating ram pump according to U. S. Patent No. 2,168,850,0onstructed in accordance with the present-invention andby aid of the accompanying drawings in'which;

Fig. 1 is atransversesection'throughthe improved pump l. I :II;

Fig. 2 is an enlarged sectional view of the inlet valve seat bushing. v.

Fig. 3 is an end view of the bushing shown in In the pump accordingto the illustrated embodiment, the pump body consists of a rectangular block ofmetal which-is bored toprovide one or more parallel holes 2'extending right through the block each to constitute a, pump bore. Each such hole is ground and lapped throughout its length slidably to receive a parallel ram 3, the fit being sufliciently close as to render packing unnecessary.

Into the outer end of each said pump bore is by the inner" swam, -Y

pressed orpushed affiangedmusliing 4 at the innerendoivwhich' is formed a conical seating 5 for an inwardly opening mushroom type inlet valve 8. Leading iromthe s'ide of'the pump-bore 2 adjacent'tlie valvefi is altransverse bore con-' stituting an outlet lzgz through which pressure liquid is discharged during thedelivery-s'troke of the associatedram 3.; Extending'back from the seatingii i's a circular recess Twhichconstitutes an inlet va'lvel" orifice common to--=aplurality of inlet passages 6 which are drilled-so asto break into the recess at their inrier ends and whichare spaced around and so astobeparallel to a can tralbore forming a guide Slfor the valve stem ill. The sum of the areas of the inletpassages should be equal toor greater-than the areaof the valve orifice; v 5 17 1,

The busliings which are machined all to the same length have each 'a flange or spigot ill at its outer end'whiclifitsinto' a circular recess':.l2: in the end faceof the-pump"body.-' To compensate for 'in-equalities in the depths l of the recess and spigots a discontinuous copperor other soft metal ring 13 is disposed at the-bottom of each recess and the flanges or spigots are pressed ontothe'se copper rings by -a' 7 cover I plate M which lie bored with inlet openings l5 aligning with the cor which would tend to build up'pressure m the recess l2 by trapping any'leakagelfrom-the' bore 2 along the exterior'of thbushin'g and thus"i-n--fcrease the'load on the cover pIateQ Thbushings themselves are asufiiciently close fit in'the pump boresto prevent any appreciable'leakagek By, making the bushiiigsfall the same length and n h same nv la b Ia: ea wo plate screwed or bfolted'toj the opposing fiat-sniff face of the pump body. the valve seats and va ves n b m n d s dden y a j 'u etelrf te r that the outer faces ofthe""valves,when closed; are all substantially the same distance from the opposing ends of the pump rams. This in turn enables the clearance between the rams and the valve to be reduced to a point where the rams and valves practically contact each other.

By making the pump bores in the form of parallel holes extending right through the pump body the machining necessary to attain the high degree of accuracy required is easily performed, whilst the resulting absence of any change in section of the pumpbore obviatesstress concentration. Due to the small leakage which is bound to occur at the very high pressure employed between the pump bore and the pump ram and the bushing respectively the pressure within the pump bore on each delivery stroke of the ram may be plotted as a curve having an amplitude chamber gradually diminishing to zero on either side of said region of maximum pressure.

The stepped or lower end of each bushing is of course formed by turning after the passages 8 have been drilled.

We claim:

1. In a high pressure reciprocating ram pump, a pump body having at least one pump bore extending therethrough an outlet leading from the pump bore; abushing fitting in said pump bore at one end thereof closely enough to prevent appreciable leakage, said bushing having an inlet valve seat at the end thereof innermost within said pump bore, an inlet orifice open to said seat, a central longitudinal bore, and a number of longitudinal inlet passages arranged around said longitudinal bore and communicating with said inlet orifice, the sum total of the cross-sectional areas of said inlet passages being at least equal to the cross-sectional area of said inlet orifice; an inwardly opening mushroom valve cooperating with said seat to close said-"orifice and having a stem guided in said central longitudinal bore of said bushing; a flange on said bushing; said pump body having an open annular recess for receiving said flange; a packing ring axially interposed between saidflange and the base of said recess; and a cover memberdismcuntably connected to said pump body and having inlet bores therein registering and communicating with said inlet passages of said bushing, said-cover member pressing said flange against said packing ring, whereby a pressure is maintained by said packing rin on said flange sufficient to prevent axial movement of said bushing due to the rapid changes of pressure that occur in the pump bore between the suction and delivery strokes of the ram.

2. In a high pressure reciprocating ram pump, a. pump body having at least one pump bore consisting of a hole extending without appreciable change of diameter through the pump body an outlet leading from the pump bore, and an inlet valve assembly forming a detachable unit; said inlet valve assembly embodying an inlet valve and a bushing fitting in said pump bore 1 at one end thereof closely enough to prevent appreciable leakage, said bushing having a valve seating at its inner end for the support of the inlet valve and a flange at its opposite end, the length of the bushing, as defined at one end by the outer face of the valve and at the opposite end by the outer face of the flanged end, being predetermined to within'very fine limits, and means for locking the bushing in place within the pump bore against the pressure developed for automatically locating the same so that when assembled the outer face of the inlet valve will almost be contacted by the opposite face of the ram at the completion of each inward Stroke, said means including a prepared locating face at one end of the pump b ody,pan open annular recess in said prepared locating face of the pump body to receive the flange of the bushing, a discontinuous ring of malleable material interposed between the flange and the bottom of the recess serving as a distance piece to prevent action displacement of the bushing and by its comwhich is a maximum in the region of the pump therein during the operation of the pump and v pressability to compensate for variations from the predetermined depth of the flange and the recess due to inaccurate machining, and a cover plate forholding the bushing within the bore with the outer face of the bushing flush with the prepared locating face on the pump body, thereby to insure the correct locating of the face of the inlet valve in relation to the plunger.

3. In a high pressure pump, in combination, a pump body having a cylindrical bore extending therethrough to define a pump chamber and a transverse bore intersecting the chamber and forming an outlet for the same, a ram reciprocable within said chamber, a bushing tightly fitting in said chamber adjacent one end thereof, said bushing having a circular recess opening at its inner end, a central bore extending from said recess to the other end of the bushing, and a plurality of inlet passages extending parallel to said central bore from said other end of the bushing to said recess, a valve seat formed on the inner end of said bushing concentric with said recess and said central bore, a valve having a stem slidably received in said central bore and a portion adapted to cooperate with said seat to interrupt communication between said pump chamber and said recess, means for retaining said bushing in a fixed position in said pump chamber including a circumferential flange formed on the bushing, said pump body having an annular recess adjacent one end of the pump chamber for receiving said flange, and a cover member dismountably connected to said pump body and extending over said bushing, said cover member being formed with passage means communicating with the inlet passages in said bushing.

JOHN MAURICE TOWLER. FRANK HATHORN TOWLER.

REFERENCES orren The following references are of record in the file of this patent:

France Aug. 1, 1923 

